Environmental sustainability is a key issue of the coal mining sector. This is because the impact of damages on activities undertaken in this sector is deemed vulnerable to environmental sustainability. The damage that occurs has an impact on environmental unsustainability. The value of environmental sustainability is set forth in the Government Regulation No. 46 of 2017 on Environmental Economic Instruments. Under this regulation, any activity that has an impact on the environment including the coal mining sector shall assess the damage it causes. The mathematical model of environmental benefits and cost of coal mining discovered by Juniah (2013), is an expansion of the extended mathematical model of the benefits and costs of Munasinghe (1997). This model can be used and implemented to assess environmental losses and determine the value of environmental sustainability of coal mining as intended by the Government Regulation of the Republic of Indonesia. The environmental losses can be minimized by utilizing water void mine as raw water. This model can also be used by government, stakeholders, and mining investors to assess the sustainability of the coal mining environment for the resulting externalities, and the utilization of mine void water as raw water.